1. Field of the Invention
This invention relates to a method and system for supercharging or subcharging an internal combustion engine without the need for rotating machinery. The electronically controlled system disclosed herein offers the flexibility of controlling the supercharger according to a variety of engine operating parameters.
2. Disclosure Information
Internal combustion engines, commonly of the reciprocating type, and most often in the form of spark ignition or so-called premixed charge engines or compression ignition commonly referred to as diesel engines, have in certain instances been equipped with supercharging devices for many years. Such superchargers have taken the form of gear driven devices, such as the well known Roots blower used with certain two-stroke cycle diesel engines, such as the Detroit diesel, and also with such spark ignition engines as such as that used in certain pre World War II Bentley automobiles. Mechanical superchargers have lately been used in certain Ford Motor Company vehicles. In any form, such mechanical devices are limited by the need to drive the device by means of an inextensible member, such as gearing or by a belt or chain. This, of course, limits the ability to control the speed and the boost ratio or other operating characteristics of the device.
Another aspect of conventional supercharging is so-called pulse supercharging. Pulse superchargers are typically rotating machines which have been controlled according to a variety of schemes.
U.S. Pat. No. 4,206,607 to Heberle et al., U.S. Pat. No. 4,563,997 to Aoki, U.S. 4,796,595 to El-Nashar et al., U.S. Pat. No. 4,798,049 to Mayer, U.S. Pat. No. 4,808,082 to Kirchhofer et al., U.S. Pat. No. 4,838,234 to Mayer and U.S. Pat. No. 4,910,959 to Dones all disclose rotating pressure wave superchargers. As with other types of rotating superchargers, certain losses are engendered by the need for bearings and other rotating components. Pressure wave superchargers produce a pulsating pressure in the intake manifold of the engine. The frequency of the pulsations is a function of the speed of rotation of the device. Controlling the speed of the rotation is somewhat difficult with a mechanically driven device, and even more difficult with a free-running device. An electronically controlled intake manifold having a supercharging device according to the present invention overcomes these problems with control because an electronically driven transducer can be operated at a frequency which is essentially independent of the speed of operation of the engine.
Transducers controlled by electronic circuitry have been employed for the purpose of influencing combustion in steady flow reactors, such as oil burners. British Patent Specification 1 495 015 to Swithenbank et al., French Patent Specification 2 490 786 to Bertrand and U.S. Pat. No. 4,644,783 to Roberts et al. all disclose steady flow, constant pressure, combustion chambers in which acoustic noise is sensed for the purpose of controlling the flow of reactants to a flame. None of the systems disclosed in these patents is directed to the supercharging of air running through the inlet manifold of an internal combustion engine.
U.S. Pat. No. 4,715,353 discloses an ultrasonic wave fuel atomizing apparatus which is not described as producing a supercharging effect.
Another aspect of the present invention relates to the concept of subcharging, in which the effective pressure within the intake manifold is depressed to a subatmospheric level in the region of the intake ports. This mode of charge air control may be desirable during engine idle, or even off-idle operation, as a means for running the engine with greater efficiency.
It is an object of the present invention to provide a tunable intake manifold system which has the capability of rapidly responding to changes in engine operating parameters.
It is an advantage of the present invention that an electronically tuned intake manifold according to this invention may be operable either by a stand-alone electronic processor or by a computer used to control spark timing, exhaust gas recirculation (EGR), fuel injection, or other operating parameters of the engine.
It is yet another advantage of the present invention that a supercharging system according to the present invention will completely avoid parasitic losses when the system is not in operation. This feature is important because traditionally supercharger systems have absorbed power from the engine at all times--e.g., even when supercharging is not required or desired.
Other objects, features and advantages of the present invention will become apparent to the reader of this specification.